A Cold Day in Erebus
by Darthkvzn
Summary: With the Mist collapsing in on itself thanks to the Chitauri invasion, and understanding of the secret, magical world around them dawning on mortals, the Olympians decide to present themselves to the citizens of Earth in the best light possible. Why they chose Nico di Angelo for this, he'll never know. CROSSOVER WITH "A GIRL WHO COULD KNOCK OUT THE HULK", Multicrossover-adjacent.


**This one-shot is a companion piece to A Girl Who Could Knock Out The Hulk's chapter 34 onwards, as well as relating to events that happen in the (obsolete/awaiting) rewrite Beating the System. I think it's enjoyable on its own, but you should be aware that the universe this takes place is a multicrossover that includes such fandoms as Supergirl, Harry Potter, Steven Universe, among others.**

 **In any case, enjoy!**

* * *

If you've ever tried to imagine the Underworld - or whatever religious equivalent you subscribe to - let me give you some friendly advice: stop. Whatever you've imagined, it doesn't do the Realm of the Dead justice. People fail to realize that _everyone_ has a soul. That means every human that's ever died could be theoretically found around Hades' domain, no exceptions. Not that you'd ever _succeed_ , of course, with the billions upon billions of Shades endlessly milling around the great Fields of Asphodel, suffering their rightly deserved fates on one of the many Fields of Punishment, or living it up at Elysium. The Underworld is _big_. That's the best way I can describe it.

Me being Nico di Angelo, son of Hades, greek god of the dead. I'm the bastard Prince of the Underworld. Hooray.

Why I was there this particular time, I didn't know. Father, though admittedly much more lenient in his treatment of me than ever, was not exactly fond of my presence in Erebus.

We demigods tend to be sore subjects for our divine parents' spouses, you see, and while Persephone was cooler with my existence than most other godly step-parents, I was still a reminder of Hades' lack of commitment.

I walked through the dark halls of Father's palace, skeleton servants pausing their activities and standing at attention, smoothing down their crumpled, ragged clothes before taking a fist to their empty chests. I barely acknowledged them. Hades had long since advised me not to encourage their sycophantic behavior.

Soon enough, I found myself at the doors of the throne room. Adjusting the carefully sheathed stygian iron sword hung at my belt, I swung the doors open.

The god of the dead lazed about his throne. He looked as intimidating as the first day I'd seen him – dark eyes, dark hair, and dark robes – poised as a panther might be, if it were given human form.

"Nico." –he said, picking at his robe. The souls trapped within the black fabric moaned in eternal torment – and really, who could blame them.

"Father." –I shortly replied, giving him a half bow.

He hummed. "It has been some time since I last summoned you, yes?" –he said, pretending not to remember.

I nodded anyway. "Almost a year and a half, I think."

Hades rubbed his chin. "That seems accurate. You are _slightly_ taller than I remember you. How does your relationship with that spawn of Apollo fare?"

If I blushed, he didn't comment. "Well enough, Father. Thank you for asking." –I said, mildly embarrassed, but genuinely thankful.

"I'm surprised he has not sent you away yet. You hardly look like the Prince of Erebus ought to." –he said, disapprovingly.

 _Of course_. Couldn't compliment me and miss the chance for a scathing remark. "Will happens to like my look."

He shrugged. "Poor taste on his part, then. Though the boy seems a good influence on your demeanor, I suppose. You no longer slouch, for one, something not even Allecto and her sisters could ever correct."

"In my defense, the Furies are somewhat hard to please." –I replied, sarcastically.

Father conceded the point. "In any case, he's a far better choice than my insufferable nephew."

I rolled my eyes. "You know, Percy and I are still friends. We _did_ save the world together a few times."

He mimicked the gesture. "And what a pity that is. The world could use a little destroying, in my opinion. Then again, I suppose my opinion is hardly worth anything, since my _brother_ had the gall to request your assistance."

"Lord Poseidon wants my help?" –I asked, perplexed.

Hades shook his head. " _Zeus_." –he spat, as if cursing. I waited for the indignant thunderclap that should've followed, but I guess those didn't reach the Underworld.

I scowled. "Whatever for?"

"It appears the mortals are growing savvy. The Titan War and the return of the Giants were bad enough, but now, with all those alleged mortal heroes, the alien invasion…the Mist barely fools them anymore. _Lord Zeus_ has grown _scared_ , and his bright idea for preserving the status quo – no doubt originally suggested to him by Athena – is to reveal our existence to the world. On our own terms, or so he claims."

I crossed my arms. This was _not_ looking good for me. "Surely that would be contradictory."

He raised an eyebrow in agreement. "My point exactly. Let them stay in the dark for however long the Mist lasts, I said. But alas, a consensus was reached, my vote be damned. _Curse_ the day Jackson gave me a seat in that infernal hall." –he sulked.

I shook my head, slightly amused. No matter how much he claimed to hate it, I knew Father was secretly pleased with his newfound status as honorary Olympian. As long as it didn't conflict with his interests, of course.

"So, what am I to do, then?" –I asked.

Hades leaned back on his throne. "There is a mortal traversing the world, searching for young heroes to recruit. He is a powerful sorcerer, I suppose, for someone utterly lacking Hecate's blood. His name is Stephen Strange. You are to present yourself to him, on behalf of the Olympians, and offer your services for whatever mission it is he seeks to complete."

Taking orders from a mortal, huh? _Wonderful_. "How long is this task supposed to take?"

Father shrugged. "Days, weeks…years? I've no clue, and neither does the Council. We're not exactly the best at keeping time straight." –he said with a cruel little smile at his awful joke. I doubt Kronos would appreciate it as much as he did.

I sighed. "Fine. I accept the quest. Why they want _me_ , I have no clue, but I suppose I have nothing better to do for the foreseeable future."

Hades waved me away. "I'm sure Lord Zeus is _ecstatic_. Now, off you go. Represent the House of Hades well, and all that. And wear the armor Persephone gave you, for Olympus' sake, you look like a vagrant!" –he shouted as I left the throne room, a fond little smile on my face.

* * *

The shadows spit my now armored self at a small apartment in Midtown. Specifically in a bedroom – one I very well knew was not my own.

"HOLY ZEUS!" –I heard a grown man scream.

Angry thunder rumbled in the distance as I struggled not to laugh my ass off at the scene. Percy Jackson, son of Poseidon, and the greatest hero since the Classic Era, pressed a bed sheet against his bare chest, eyes wide, his hair an inky black mess.

"Cousin." –I smoothly replied. In another time, I might've blushed at the sight, but I was quite used to my former, unrequited crush.

Annabeth came out of the adjacent bathroom dagger first, clad only in a see-through nightgown and underwear, yet managing to make herself look lethal. "Nico?" –she asked, her eyes widening.

"Other cousin." –I said, turning towards her.

The daughter of Athena put the celestial bronze weapon away, then walked up to me and gave me a big hug. "It's been too long." –she said happily.

I shrugged. "Just a couple of months, really. I've been a little busy."

Percy grudgingly walked up to me, and shook my hand. "I'm _sure_ it could've waited a few hours." –he said, though his shaky smile was genuine.

I smirked. "Well, _duh_. But where's the fun in that?"

Annabeth shot her boyfriend an amused look. "You _did_ say he could drop by anytime."

He scoffed. "Remind me to stop _saying_ things. Only serves to get us in trouble."

The blonde swat him, which earned her an indignant look. She rolled her eyes. " _Anyway_ , what brings you here, Nico? And armored, too." –she asked, noticing the metallic plate under my admittedly pretentious trench coat, her mind already running through the possibilities.

I shrugged. "A quest, actually. If you could call it that. It appears Lord Zeus has need of my particular set of skills." –I said, cryptically.

Percy frowned. "Zeus? Doesn't he hate your guts? And, y'know, almost everyone else's?"

Thunder rumbled again. Just a coincidence, obviously. "That's what I thought, too, but it looks like he's willing to make an exception. That, or he needs a particularly _expendable_ demigod. You know of the issues with the Mist, I wager."

Annabeth nodded. "Yeah. Ever since Seaweed Brain here couldn't keep it in his pants." –she said, snickering.

"There were _aliens_ flying around. I couldn't afford to miss that action." –he tried to defend himself.

"A surprise alien invasion is no excuse for taking your sword out and waving it around in plain view of the mortals, cousin." –I chastised him.

Percy guffawed. "Ok, that one was good."

I laughed. " _Anyway_ , the Olympians want me to meet some magic wielding mortal. Guy by the name of Stephen Strange."

Annabeth frowned. "I thought that guy was dead."

"You know him?" –I asked.

She shrugged. "I know _of_ him. Barely, at that. He was – or, I guess, _is_ – a very famous surgeon. He got in a car accident, a few years ago, and his hands got… _damaged_ , bad enough that he couldn't operate anymore. No one's seen or heard from him since. Everyone just kind of assumed he died."

I shook my head. "Well, he's _definitely_ not dead." –I told them, "My 'death senses' would've tingled."

Percy had a scowl on his face. "Why are they sending _you_ , though? I mean, not that I _want_ to go, but it's because of me that the Mist is broken."

Every demigod knew that, of course. Percy, soft idiot with a heart of gold that he was, hadn't been able to stop himself from intervening during the Battle of Manhattan, a little under two months ago. While the Avengers did their thing, Percy had taken to the streets, rallying the terrified citizens behind him, protecting the mortals with his water powers and killing the aliens – which apparently counted as 'monsters', for celestial bronze – with his trusty sword, Riptide.

"Percy, let's be honest here. We both know you've earned the rest. You beat the odds. You have a life, here, finally. Meanwhile, I'm still _me_. Sure, I've got Will, but that's about it. No family, no job, no real place to stay at." –I reasoned.

He tried to talk, but I shut him up. "And _don't_ say Camp Half-Blood, or Camp Jupiter. You _know_ I don't feel the same way about them as you do." –I said.

Percy seemed deflated. "You're still Ambassador, though…" –he half-heartedly tried to argue.

I rolled my eyes. "That was never a _real_ job. Just a made-up title Reyna made up to fit me into the Camp's structure without causing a fuss. And it's not like greeks and romans need help with diplomacy anymore."

Annabeth looked at me, smart grey eyes framed by thick bruising, a glaring reminder that their unfortunate extended stay in Tartarus was still a heavy burden upon their psyche. "You're sure?" –she asked me.

I nodded. "You guys deserve your peace. Besides, the gods want me to go. Who am _I_ to question their wishes?" –I asked, sarcastically.

My best friend and I shared a look. I glanced at her belly, and she barely nodded. I _knew_ I felt more than three life aurae in the room. I nodded towards Percy, questioningly, and she shook her head.

Meanwhile, the son of Poseidon looked at both of us. "Ok, it's _too_ _early_ for one of your creepy silent conversations. You _know_ I can't understand what you're saying." –he complained.

Annabeth wrapped her arms around his neck. "Oh, don't worry about it, Seaweed Brain. You'll know soon enough."

I snickered as I willed the shadows of the room towards me, feeling their comforting cold embrace slowly envelop me. "Good luck…"

The last thing I heard from the real world was a fairly anxious demigod, asking what I meant by _good luck_.

* * *

My last stop before I went on with my quest was at Camp Half-Blood, of course.

The Camp grounds were quiet, as the moon shone brightly above my shadowy form. I could hear the harpies in the distance. I was hardly worried – they steered way clear of me, with my supposed 'death stench' and all. I walked the short distance to the Apollo cabin, the usually flamboyant golden exterior muted during Lady Artemis' turn riding across the sky. I summoned a clump of dirt to my hand, packed it into a misshapen, rock-hard ball, and tossed it at one of the windows.

It didn't take long for Will to come out, looking equal parts annoyed and joyful at seeing me. "What in Hades are you doing here so late, Romeo?" –he asked me, drowsily.

I raised an eyebrow. "You wound me, beloved. Who's this Romeo you speak of? I'll send hordes of the undead after him!" –I said jokingly.

He rolled his eyes. "Sorry. _Nico_."

"I came to say goodbye, actually." –I said, a little sad.

Will frowned. "Where are you going?" –he said, uncertainly.

"I actually don't quite know. Lord Zeus seems to have it out for me-" –I said, and thunder boomed. I glared at the sky. "Oh, shut up, you _know_ you do." –I remarked, which must've been true, because no further thunderclaps were heard. " _Anyway_ , the Olympians have a quest for me. I have to meet some old mortal and pledge my services to him for the duration of the quest. I wanted to see you before I looked for him – who knows how long he's gonna need me for." –I explained.

He nodded slowly. "This mortal, what's his name?"

"Strange, I think. A former surgeon, if I'm not mistaken."

Will groaned. "I _hate_ the gift of prophecy." –he muttered.

I raised an eyebrow. "Come again?"

He sighed. "I guess I had a prophetic dream, three days ago. Nothing major, y'know – I'm hardly the Oracle – but I've heard of this man before. I should've told you about it, but I just thought it was a weird dream at the time." –he confessed.

"Don't worry about it. What was the dream about?" –I asked him gently.

"It's a little hard to remember, but I think there was a man in the sky. He was dressed in red and black robes, old-school, but…somehow, fitting. I thought he was strange, and that's how I knew his name. I could see the Sound from where he stood. Some kind of metal platform, suspended in the sky. That's all I've got, sorry." –he said apologetically.

I smiled. "It's more than enough, Will. Thank you."

He nodded, though his expression was still glum. "So, no clue how long this quest will last, then?" –he asked.

"No. Father gave it to me and _he_ didn't seem to know. He says hi, by the way." –I said. Not _strictly_ true, but Lord Hades did seem approving of my boyfriend.

Will gave me a sarcastic look. "Lord Hades, god of the dead, and King of the Underworld, told you to say _hi_ to me." –he stated in disbelief.

I coughed sheepishly. "Maybe not his _exact_ words, no, but he did seem…content, about us."

He searched my face skeptically. " _Uh_ _huh_. I'll take your word for it, Nico. Just…take care, will you?" –he asked me.

I hugged him tightly, not resisting in the slightest when it turned into a soft yet passionate kiss. "I'll do my best." –I told him, amused.

As we separated, I thrust my hand out towards the ground, which rumbled slightly. The skeletal remains of a horse climbed out of the shifting soil, assembling into an undead steed as they did. Before I could even think of mounting it, lightning fell from the sky, striking it and scaring the Hades out of both of us. When I opened my eyes, instead of seeing the charred bits of bone I expected to see, I found my horse had gained flesh and blood – barely, as the ebony skin clung to its skeletal frame.

Even better, it now had _wings_. Large, bat-like ones, but still, a rather appropriate facsimile of a pegasus. It had a note, gilded in gold, hung around its bony neck. Glowing red eyes regarded me curiously. I opened the note, which read, in fancy golden cursive:

 _To my rather ungrateful nephew:_

 _I give you leave to traverse my domain, as the circumstances of your quest require it. I have given back life to your undead steed as a Thestral, a magical creature rarely seen in this age. It is smart, tenacious, and loyal. Not unlike you, I suppose. Ride the skies well, Prince of the Underworld._

 _Lord Zeus, god of the skies, King of Olympus_

Will, who was looking over my shoulder, regarded me fearfully. "Just _what_ are you getting into, Nico?"

I shook my head, equally awed. "I don't know, but I think I _have_ to find out, now."

* * *

 **This was written a veeery long time ago, and I think it shows. but I tried to bring it up to my modern standards as much as possible.**

 **Side note, the Thestral is named Shadowmere, because Nico is a dang nerd.**


End file.
